Absorbents pads fabricated of air-laid fiberized pulp lap and disposable diapers, incontinent briefs, underpads, and catamenial pads utilizing such pads are known in the prior art. Such air-laid structures may be formed on a paper tissue and an example of fiberizing or disintegrating pulp lap and felting thereof for manufacture of such a product is disclosed, for example, in U.S. Pat. No. 3,519,211 entitled "Disintegration Process For Fibrous Sheet Material", which patent issued to Sakulich, et al. on July 7, 1970, U.S. Pat. No. 3,750,962 entitled "Disintegration Process For Fibrous Sheet Material", which patent issued to Morgan, Jr. on Aug. 7, 1973, and U.S. Pat. No. 3,825,652 entitled "Apparatus For Preparing Airfelt", which patent issued to Buell on July 23, 1974. The disclosure of the aforesaid patents are hereby incorporated herein, by reference, as fully and completely as if physically reproduced hereat and throughout this application the terms "air-laid" and "airfelt" pads are intended to refer to a product such as that formed in accordance with said patents.
It has also been previously suggested to fully enclose such an air-laid felt pad or bat within a tissue envelope to aid in supporting the felt during processing, including converting, and to aid in preventing disintegration thereof during use. See, e.g., Kalwaites U.S. Pat. No. 3,444,859; Schutte U.S. Pat. No. 3,741,212; Costanza et al. U.S. Pat. No. 3,769,978.
It has also been recognized that increased wicking and fluid transfer or transport within such a structure may be accomplished by densifying or compressing the structure to provide an increased density thereof as suggested in, e.g., Duncan U.S. Pat. No. 3,592,194; Krusko U.S. Pat. No. 3,721,242; and DeKnight U.S. Pat. No. 3,769,978. It has even been suggested that a one-directional generally sinuous pattern of compressed narrow strips may produce enhanced distribution of moisture in such a structure longitudinally along such strips. However, such narrow compressed strips have also been recognized as barriers reducing transverse moisture transport and also resulting in a stiffer and less soft product. See, e.g., Morin U.S. Pat. No. 2,788,003. It has also been suggested that the compressed narrow strips may be arranged in various patterns, one such pattern comprising a plurality of intersecting lines. See, e.g., Mesek U.S. Pat. 4,259,387. Further, it has been suggested that compressing a pad of the general type referred to above so as to decrease the thickness thereof and increase the bulk density, not only creates increased wicking but, in addition, may produce increased flexibility. See, e.g., Gobbo, Sr. et al. U.S. Pat. No. 3,065,751. However, the mere increase in flexibility does not necessarily result in increased softness and what the prior art has apparently not recognized, is that softness and flexibility are not the same and, in fact, structures exhibiting high flexibility may provide a very low softness impression to a user. Moreover, the prior art has also apparently not recognized that subjective surface dryness impressions are not necessarily consistent with objective tests for surface dryness and, in fact, subjective surface dryness impressions may be diametrically opposite of objective surface dryness test results.
One invention that has made good progress in addressing the aforementioned concerns is disclosed in U.S. Pat. No. 3,908,659, entitled "Absorbent Pad Structure, Diaper Construction Utilizing Same and Methods of Manufacture Thereof", which patent issued to Wehrmeyer et al. on Sept. 30, 1975. U.S. Pat. No. 3,908,659 discloses an embossing pattern for an absorbent core, which pattern is formed by dry pattern densification, and which pattern comprises an array of generally circular low density tufts which are separated and surrounded by bilaterally extending non-linear and generally sinuous regions of higher density. Such a pattern provides high softness impression together with high moisture wicking and transport and high surface dryness impression.
Bearing in mind the foregoing, it is a primary object of the present invention to provide a novel and improved absorbent pad structure.
Another primary object of the present invention, in addition to the foregoing object, is to provide such novel and improved absorbent pad structures having optimized liquid distribution and wicking capabilities as well as surface dryness and softness impressions.
Yet another primary object of the present invention, in addition to each of the foregoing objects, is the provision of such novel and improved absorbent pad structures particularly constituted for use in disposable diaper structures, underpad structures, incontinent brief structures, and catamenial pad structures fabricated thereof.
Yet still another primary object of the present invention, in addition to each of the foregoing object, is the provision of a novel absorbent pad having relatively low density tuft regions which are separated and surrounded by channels, wherein the channels comprise relatively intermediate density storage regions and relatively high density transport regions.
Yet still another primary object of the present invention, in addition to each of the foregoing objects, is the provision of a novel absorbent pad fabricated of airfelt, preferably within a tissue envelope, subjected to dry pattern densification, as by patterned compression, to provide a pattern of alternating horizontal rows in the longitudinal direction of rhombus shaped tuft regions and pairs of triangle tuft regions, wherein the rhombus and pairs of triangle shaped tuft regions are staggered in the lateral direction and are surrounded by bilaterally extending, linear and preferably sinuous channels. The channels comprise relatively high density transport regions which are separated and surrounded by relatively intermediate density storage regions which have a density greater than the density of the tuft regions but less than the density of the transport regions.
The invention resides in the combination, construction, arrangement and disposition of the various component parts and elements incorporated in improved absorbent pads constructed in accordance with the principles of this invention. The present invention will be better understood and objects and important features other than those specifically enumerated above will become apparent when consideration is given to the following details and description, which when taken in conjunction with the annexed drawings describes, discloses, illustrates and shows the preferred embodiment or modification of the present invention and what is presently considered and believed to be the best mode of practicing the principles thereof. Further embodiments and modifications may be suggested to those having the benefit of the teachings herein and such other embodiments or reserved especially as they fall within the scope and spirit of the subjoined claims.